Seth e



(No Modeh) S. E. BEEDY.

TELEPHONIO TRANSMITTER.

Patented Jan. 10

UNITED STATES PATENT OFFICE.

SETH ,E. BEEDY, OF FARMINGTON, MAINE, ASSIGNOR Oll ONE-FOURTH TO DANIEL W. AUSTIN AND JOHN J. LINSCOTT, OF SAME PLACE.

SPECIFICATION forming pa:+ of Letters Patent No. 376,060, datedJ'anuary 10, 185 8.

(No model.)

To aZZ whomjb may concern.-

Be it known thatl, SETHE. BEEDY, a citizen ofthe United States, residing at Farmington, in the county of Franklin and State of Maine, have invented new and useful Improvements in Telephonic Transmitters, of which the following is a specification.

My invention relates to that class of microphone or carbon transmitters in which the to position of surface-contact of the electrodes is varied, and at the same time modifications are produced in the pressure of the electrodes, thus modifying the current passing through the electrodes in a manner suitable for teler5 phonic purposes.

The object of the invention is to provide simple and effective means for causing the carbon electrode carried by the diaphragm of a telephonic transmitter to approach or recede from the electrode mounted upon a pivoted and self-adjusting support or carrier. Furthermore, to cause said movable electrode impinging upon the lateral surface of the electrode on the diaphragm to exert a variable pressure in accordance with the amplitude of the vibrations of the diaphragm.

The invention also has for its object to provide an electrode which shall present as small a surface as possible to asecond electrode-capable of sliding thereon, and thus give delicacy in the adjustment of the contact and pressure upon the electrodes with a View to transmitting the sound-vibrations to said electrodes in the most effecti ve manner.

It is also to be observed that in my instrument the initial or normal pressure causing the movable electrode to always remain in contact with the electrode fixed on the diaphragm is obtained by an adjustable weight, and in addition thereto the movable electrode is mounted on a resilient or flexible arm, which will cause a variation of pressure between the two electrodes in accordance with the degree of vibration of the diaphragm by sound-waves.

5 I thus combine in my invention the principle of changing the position of surface-contact of the electrodes and the variation of pressure between the same in a most simple and effective manner. c

The present invention relates to that class of telephone-transmitters in which an electrode carried by a diaphragm or vibrating plate cooperates with a second electrode mount-ed onv a movable support, so as to effeet a change of the relative positions of the 53 two electrodes by the vibrations of the diaphragm and produce variations of tension or modulations of the eclectric current sent to line in order to reproduce articulate speech.

The object of the invention is to provide a 6:) transmitter in which the electrodes for varying the tension or modulating the electric current operate in a most perfect and satisfactory manner to reproduce speech with great certainty and precision.

To these ends the invention consists in the construction and arrangement of parts,which will be hereinafter more fully described, and then set forth in the claims.

In the accompanying drawings, Figure 1 is a view of a telephone with the door or base thrown open, giving a rear plan view of the operative parts, while Fig. 2 is a section on the line 00 00.. Fig. 3 is section of the metaltipped carbon electrode, and Fig. 4 a perspec tive'of the cupped-lever receptacle therefor.

7 is an ordinary box for receiving and protecting the apparatus, having hinged to it the lid or cover 6, which serves as the base upon which the operative parts are mounted.

l is the diaphragm, madeof sheet metal or. any other suitable material, which is secured in position by therings 2 5. Of these rings one, in this instance 2, is slightly larger than the other, 5, and has cut or formed inone of its faces a recess, 3, bounded on its exterior by a flange, 4. Into this recess 3 the diaphragm' l is laid and thereupon the ring 5 is placed. Screwsor pins (1 a pass through these rings and the diaphragm into the base 6, securing'all o thereto and preventing any lateral movement or displacement of the diaphragm and its re tainingrings. Upon the diaphragm in any suitable manner, in this instance by the cup or socket 8, a 5

piece of carbon cylinder or pencil is secured,

forming one of the active electrodes for varying and controlling the current. The other electrode is formed of a pointed or tapering ended pencil or cylinder, 10, which may be formed entirely of carbon,'but preferably is made of a carbon body and is provided with a metal tip, 11, either by coating or plating the tip with the desired metal, or, as shown, by the insertion into the body or" 10 of a tapering I05 7 ended pencil of metal- The metal used should be one ofgreater conductivity than the carbon. This electrode is secured in a cup or socket, 13, on a support or holder. This cup or socket 13 is formed or placed at one end of a lever pivoted at 16. The end 14, upon which the socket is placed, is made springy or resilient, while the other end, 24, is rigid and stiff and is adapted to carry a weight, which may be moved thereon to or from the pivot or fulcrum 16, so as to vary and adjust the normal contact off) and 11. To this end it may be screwthreaded and the weight 15 a nut, or it may be plain and the weight slide thereon and be secured at any position by friction or by an adjusting-screw passingtherethrough and taking upon 24 in a manner well known in the art. This lever is mounted in the arms 18 18 of a bracket, 17, which in turn is secured to and upon the base 6.

Upon the front of the door is mounted in proper relation to the diaphragm the ordinary mouth-piece, M, for concentrating the sounds to be reproduced upon the diaphragm. The door is also furnished with some device for holding it closedprcferably a small lock-to prevent unauthorized tampering with the interior.

From anysource of electricity-say the battery Bthe usual cirouit-connections, 19 20, are formed to the two electrodes, one of which may be connected directly to the line, or, as is now preferred in telephony, one, as 20, may be the primary wire of an induction-coil, I,

whose secondary coil connects to the line-circuit 21 22.

In operation, the weight 15 is adjusted to cause the normal contact of 9 and 11 to be that found to be most desirable. Then, upon vibration of the diaphragm and consequent movement of 9, the latter slips or slides over the point 11, varying the points of contact of the two, and also, through the resilience of" 14, permitting a slight vertical movement of 11, varying the force or firmness of their contact. These variations of contact vary and control the current and cause it to take upon itself the undulatory character necessary for the re- Y production of the actuating sounds.

I am fully aware of the following method of transmitting speech, viz: throwing upon a line electric undulations by increasing or diminishing the resistance of the circuit by the movement in frictional contact of electric conductors in accordance with the vibrations of a diaphragm responding to atmospheric vibrations. Furthermore, I. do not deem myself to have invented a pivoted electrode-carrier provided with a spring-arm and a weight. My invention, as above fully described, involves only the special construction and adaptation of devices going to make up an instrument which is very sensitive and efficacious in every way, and whose use is not attended with breaks.

In a patent granted to me on the 27th day of October, 1885, No. 329,001, the application for which was filed August 1, 1884., I have set forth a telephonic transmitter constructed on the general principles of the one now presented. In said patenta pivoted and weighted lever carries a carbon roller, which impinges against a carbon stick on the diaphragm, and produces the changes in the electric current necessary for the transmission of speech by frictional contact alone. In the instrument embraced in the present case the operation of the electrodes is to produce the dual effects already statedviz., to vary the points of surface-contact of the two electrodes, and also to vary the force or firmness of their contact, the latter result being attained by the presence of the resilient portion of the electrode-lever. This is due to the fact that the vibrations of the diaphragm and the electrode mounted thereon cause a jarring of the electrode-lever, so as to vary the degree of pressure with which the lever-electrode bears upon the electrode on the diaphragm. It is a. very important feature of my invention to contrive and locate the electrode-bearing lever in such a manner that the electrode mounted thereon will bear upon some portion of the peripheral surface of an elongated electrode mounted on the diaphragm. By such disposition of parts the diaphragm-electrode can glide over the leverelectrode, so as to vary the length of the path in the electrodes through which the current passes, and also produce the changes of pressure between the two electrodes, as has already been stated.

Having thus described my invention, what I claim is- 1. In a telephonetransmitter, the combination,withadiaphragm having an elongated straight-surfaced electrode secured thereto, of a swinging or pivoted lever having a balance-weight at one end and a fixed electrode at the other end, the latter electrode extending at right angles to the lever or support and impinging against the straight peripheral surface of the diaphragm-electrode, substantially as herein set forth.

2. In a telephone-transmittcr, the combination,with a diaphragm having an elongated electrode secured thereto, of a straight swinging arm or lever provided with a resilient or springy portion, an electrode rigidly secured to the latter and bearing upon the peripheral surface of the diaphragm-electrode, substantially as described.

3. In a telephonic transmitter, the combination of the straight electrode-bearing lever formed of a screw-threaded portion, a resilient portion, a cup and journals, with the electrode inserted in the cup, an adjustable weight, a support for the lever, and a diaphragm carrying an elongated electrode, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

SETH E. BEEDY.

XVitnesses:

ALBERT H. Noanrs, Jos. L. CooMBs. 

